1. Field of the Invention
This invention relates to a pointer for a three dimensional display system and, more specifically, to a modulated focussed light source for locating a point in three dimensional space in a real time three dimensional display.
2. Brief Description of the Prior Art
It has been known in the prior art to modulate or scan a beam, such as a laser beam and then to project the scanned beam onto a screen. Examples of such systems are set forth in Baker Patent Nos. 3,471,641 and 3,549,800.
A system which is superior to the systems denoted hereinabove and other known systems is disclosed in the copending application of Felix Garcia, Jr., Serial No. 07/390,473, filed Aug. 3, 1989, the disclosure of which is incorporated herein by reference. In accordance with the system set forth therein, there is provided a three dimensional display system which is not substantially affected by G forces and wherein the size of the displayed image and screen is determined by the size of a disk and motor. The system can be used, for example, in business and industrial uses, such as solid animation, radar display, molecular research, resonant frequency and harmonics display, military, computer graphics and the like.
The system includes a disk-like screen connected to the end of a motor shaft. The disk is attached to the shaft of a motor preferably at a 45 degree angle to the shaft, though this angle can be varied to provide a larger or smaller height or z-axis dimension so that, as the disk rotates, a displacement of any given point thereon along the z axis takes place. The image is formed on the screen by projecting a light beam, such as from a laser, through a modulator and toward a scanner which produces an x-y scan of the beam on a screen, the screen herein being the disk discussed hereinabove. The disk can be translucent, such as lucite, so that images can be projected thereon onto the front and/or rear surfaces thereof.
The modulation or strobing of the scan is synchronized with the rotating disk by control of the motor speed and/or the strobe rate so that a three dimensional pattern appears on the screen. It can be seen that any point on the x-y scan from the scanner which impinges upon the screen will move along a z-axis direction since the screen or disk at that point produces such z-axis movement. This movement of the displayed image provides the three dimensional effect. The adjustment of the angle between the disk surface and the x-y plane of the scanned x-y image will determine the z dimension or height of the three dimensional image, the disk angle being adjustable on-line, if so desired.
The disk is preferably a planar opaque screen for receiving a scanned image thereon on one surface thereof. The screen can, however, take different forms such as, for example, being translucent, such as lucite, and thereby being capable of receiving a scanned image thereon on both major surfaces or transmitting images received on one surface thereof to the opposing surface for viewing or other operation. The lucite disk can be in the form of a pair of angularly truncated cylinders which fit together at the angularly truncated surfaces to form a new cylinder wherein the surfaces at which truncation takes place are translucent. In addition, the screen can take on shapes other than planar, it merely being necessary that at least some portion thereof move in the z-direction during rotation thereof while projection of the x-y image thereon takes place to provide the three dimensional image. Furthermore, the disk can be placed in a gas filled CRT with the image impinging thereon being the scanned beam of the tube. Phosphors can be disposed on the disk which, when excited, form the three dimensional image. Still further, the screen can be planar and disposed normal to the projected x-y image.
While the above described application of Garcia provides a real time autostereoscopic multiplanar 3-D display system, there has been no provision for accurately locating and pointing to any point within the display in real time apart from the scanner itself, such as by directing a pointer to a specific point in the display to point out items during the course of a lecture or discussion in the manner of a pointer on a motion picture screen.